dashp/src/internal/is.js

Utilities for monadic promises.

export const isFunction = (f) => typeof f === "function";
export const isThenable = (p) =>
  p instanceof Promise ||
  (Boolean(p) &&
    (typeof p === "object" || typeof p === "function") &&
    isFunction(p.then));
// eslint-disable-next-line prefer-destructuring
export const isArray = Array.isArray;
export const isError = (e) => toString.call(e) === "[object Error]";